Likewise, Elrond had already shown the legitimacy of his powers to them repeatedly in the past.
After Ferdinand lived in the empire without meeting whoever it was, he was so sure they must have made a mistake or were simply saying things to make him act.
The other primordial dragons sent here all met their mate before they turned "twenty."
It was something they instantly knew at a glance upon encountering the said person.
Yet, Ferdinand did not feel anything with all the ladies they made him meet.
Thus, Ferdinand insisted on returning to Estrella and letting Raymond takeover the throne.
But Elrond refused to let him return, saying things like he must meet his mate no matter what.
The Dragon God even threatened to extend Ferdinand's life even longer if he kept being stubborn.
Thus, Ferdinand had no choice but to do as they say after that.